New BMW M3 sedan set for 2013 debut

BMW is less than nine months away from officially revealing its all-new fifth generation M3 – the first to receive turbocharged six-cylinder power by way of a largely unique engine developed at the German car maker's heavily cloaked M division engineering workshop on the outskirts of Munich, Germany.

The four-door performance sedan, known under the internal codename F80, is planned to make an initial appearance in lightly veiled concept car guise at the Geneva motor show next March, where the external appearance and mechanical package of BMW M division's eagerly anticipated Audi RS4 Mercedes-Benz C63 AMG rival will be revealed for the first time.

A showroom ready version of the new car complete with its production interior is then set to get an airing at next year's Frankfurt motor show, according to key BMW sources.

On this timing, the new M3 should be ready for Australian sales in early 2014 at prices that will likely rise above the $154,000 of the previous M3 sedan owing to slightly higher positioning and greater levels of standard equipment.

In a departure from the previous four generations, the new M3 will be launched exclusively as a four-door sedan– a move that brings it into line with the larger and more expensive M5.

A trio of sleeker styled models, including a follow up to today's coupe and cabriolet as well as a new four-door Gran Coupe variant, will then be added to the BMW line-up in time.

But as part of a new naming process they will eschew the iconic M3 name for a new M4 nomenclature – mirroring the move BMW has taken with the latest M6, which comes as a coupe and cabriolet and, as Drive can reveal, will also be sold in Gran Coupe guise.

The new M3 will follow the example of the larger M5 in receiving a series of highly functional but visually subdued styling changes over the standard 3-Series sedan. The new look is credited to Uwe Weidehase, long time head of design at BMW's M division.

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Included among the changes is a deeper front bumper with large cooling ducts for its new forced induction engine, lightly altered kidney grille, wider front fenders with signature air vents, unique exterior mirrors, wider sills underneath the doors, subtle boot lip spoiler and a deeper rear bumper that incorporates a fully functioning diffuser to more efficiently cool the rear differential as well as BMW M division's traditional quad tailpipe treatment.

Despite BMW's increasing commitment to carbon fibre construction with its upcoming i brand, the M3 will retain an all steel platform structure.

However, certain parts of the body shell, including its bonnet and doors, will be fashioned from aluminium in a move aimed at seeing it hit the scales below the 1605kg of the now discontinued sedan version of the existing M3.

The M4 coupe will go one step further by receiving a carbon fibre roof in a move aimed at providing it with the lowest possible centre of gravity – something that will also be reflected on the M4 Gran Coupe.

Speculation to the M3's mechanical package has been rife for some time now, with some even suggesting the new car was in line to receive a 3.3-litre V6 engine based around the 90-degree architecture and 549cm3 individual cylinder capacity used for the larger M5's 4.4-litre twin-turbo V8.

"This is utter rubbish," says a high ranking Drive source. "Packaging considerations aside, there is no reason for BMW to abandon its tradition of straight six-cylinder power – neither from a performance nor a production standpoint."

Instead, the new M3 and its M4 siblings are set to receive a heavily reworked version of BMW's 3.0-litre turbocharged inline six-cylinder engine. Details remain scarce, but don't expect much of the standard direct injection petrol unit to remain.

As is tradition at BMW's M division, the engine has been extensively re-engineered with a strengthened aluminium and magnesium block and heavily altered cylinder head forming the basis of what one insider described as a new powerplant that, he contends, goes under the internal working name S55.

The decision to go with a turbocharged engine will bring an end to an illustrious 27 year era of naturally aspirated powerplants for the M3 when the new model arrives.

Among the myriad modifications brought to the new engine over the standard N55 will be a new induction system using twin variable geometry turbochargers with twin-scroll technology – a measure already seen on the M5's V8 engine.

Early talk of the M3's new powerplant adopting a tri-turbocharger set up similar to the 3.0-litre inline six-cylinder diesel engine just released in versions of the X5 and X6 is now denied by BMW officials.

The new unit will also receive the latest incarnation of BMW's bi-vanos variable valve time. Unclear at this stage is whether BMW's M division has increased the 3.0-litre capacity of the engine for the new BMW M3.

In a bid to match the performance levels of the recently facelifted Audi RS4/RS5 and Mercedes-Benz C63 AMG sedan/coupe, the new engine is expected to deliver in the region of 335kW and around 470Nm of torque – some 26kW and 70Nm more than the fourth generation M3's naturally aspirated 4.0-litre V8 engine.

By comparison, the RS4/RS5's naturally aspirated 4.2-litre V8 kicks out 331kW and 430Nm while the C63's naturally aspirated 6.2-litre V8 provides 336kW and, owing to its generous capacity, some 600Nm.

The new M3 engine will come allied to a standard seven-speed double clutch gearbox – essentially the same unit used in the M5, albeit with altered ratios, offering both manual and automatic modes.

As has become tradition, drive will be doled to the rear wheels via an electronically controlled variable M differential offering 100 per cent lock up.

For the first time since its inception in 1986, there will be no manual gearbox for the M3.

Plans for a four-wheel-drive version of the new car were considered but eventually rejected. Instead, BMW is planning to introduce a less powerful M335i as part of its new M Performance line-up that, like the recently confirmed M135i, will be available with the choice of both rear and four-wheel drive. It will also be available in sedan and Touring bodystyles.

In line with BMW's EfficientDynamics initiative, however, the new M car will receive fuel saving features such as automatic stop/start, smart alternator and individual on-demand operation of engine ancillaries, including the oil and water pumps.

Underpinning the new M3 will be an all-new aluminium-intensive chassis with a longer wheelbase than the arrangement used in today's models. The track widths will also be widened giving the new car a significantly larger footprint.

The suspension retains MacPherson struts up front and multi-links at the rear. However, the geometry has been completely reworked.

Standard wheels for the new BMW M3 will once again be 18-inch in diameter.

The new car will also offer dynamic damping control.

Further changes to the new M3 centre around the steering, which adopts electro-mechanical operation for the first time.

Electronics will play a key role in the overall dynamic set-up with FlexRay high speed data transfer providing more spontaneous interaction between the various driving aids, including dynamic stability control.